Palaeokarst‐influenced depositional and diagenetic patterns in Upper Permian carbonates and evaporites, Karstryggen area, central East Greenland

• Published in: Sedimentology
• Main Authors: SCHOLLE, PETER A., STEMMERIK, LARS, ULMER‐SCHOLLE, DANA, LIEGRO, GIUSEPPI DI, HENK, F. H.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1993
• Subjects: Greenland; Jameson Land; Wegener Halvø; East Greenland
• Online Access: http://dx.doi.org/10.1111/j.1365-3091.1993.tb01368.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1365-3091.1993.tb01368.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-3091.1993.tb01368.x

ABSTRACT The Karstryggen area of eastern Greenland represents the western edge of sedimentation in the Jameson Land Basin, an arm of the northern Zechstein seaway. Upper Permian strata of this area were deposited as two major sequences. The first marine incursion transgressed largely peneplaned Lower Permian strata and deposited thin, paralic conglomerates, sandstones and shales (the Huledal Formation) followed by a thick package of carbonates and evaporites (the Karstryggen Formation). Although the Karstryggen Formation represents the transgressive maximum of this sequence, it contains only marginal or restricted marine strata, including micritic, stromatolitic and peloidal carbonates and thick, but localized, bedded gypsum deposits. These lithofacies indicate that relatively arid climates prevailed in this basin, as in most of the Zechstein region. A major regression, associated with a change to a more humid climate, terminated Karstryggen sedimentation. Pre‐existing evaporites and carbonates underwent diagenetic alteration, including widespread calcitization and dissolution of gypsum. More importantly, topographic relief in excess of 120 m was generated by fluvial drainage systems and karstic sinkholes. A second marine incursion, accompanied by a return to a semi‐arid climate, drowned this high relief topography, producing a complex sequence of strata (the Wegener Halvø Formation) in which sedimentation was greatly influenced by the rugged underlying terrain. Marine cemented algal‐molluscan grainstones draped pre‐existing palaeotopography during the initial stages of flooding. Continued drowning led to differential sedimentation on ‘highs’ and in ‘lows’. Oolitic and bryozoan‐brachiopod grainstones formed as shoals on the crests of most prominences, whereas shales, conglomeratic debris flows, evaporites, or oolitic turbidites were deposited in the lows. More restricted sedimentation took place in the westernmost areas which lay closest to the mainland shoreline and were situated to the west of a ...